Closure mechanism for cooking range ovens



July 13, 1954 E. s. POLLOCK ET AL 2,683,447

CLOSURE MECHANISM FOR COOKING RANGE OVENS Filed May 5, 1952 3 Sheets-Sheet 1 M w, M. TWHHHQHH wamnhnri. -I w=w=i F w 4 w a w, w& M a 3 i w n 2 m m ll-DI x \IIIIIIIIIII July 13, 1954 5, PQLLOCK ET AL CLOSURE MECHANISM FOR COOKING RANGE OVENS 3 Sheets-Sheet 2 Filed May 5, 1952 July 13, 1954 E. s. POLLOCK ET AL CLOSURE MECHANISM FOR COOKING RANGE OVENS Filed May 5, 1952 llmx- IIIIIIIIIIIIIQWIIIIII Patented July 13, 1954 CLOSURE MECHANISM FOR COOKING RANGE OVENS Earl S. Pollock, Lexington, and Edward H. Grofl, Leonard K. McFarland, and Hey L. Stichler, Mansfield, Ohio, assignors to The Tappan Stove Company, Mansfield, Ohio, a corporation of Ohio Application May 5, 1952, Serial No. 286,143

1 Claim.

This invention relates generally to cooking range oven doors of the drop type which are hinged along the bottom thereof and swing outwardly and downwardly from a vertical closed position to a substantially horizontal open position. More specifically the invention relates to the counterbalancing mechanism therefor, and is a modification of the Oven Door Stop Mechanism disclosed in the copending application of Edward H. Grofi Serial No. 285,142 filed May 5, 1952.

Cooking range oven doors are relatively heavy as they must be thoroughly insulated and constructed to stand hard usage. Means must be provided to limit the open position thereof to substantially horizontal and means must also be provided to hold the door tightly closed in order to prevent the escape of heat from the oven. Means should also be provided to sub stantially counterbalance the door in all positions between closed and fully open positions. Prior counterbalance mechanisms for doors of this type are quite complicated due to the fact that the force of gravity acting on a door is constantly changing as a door of the drop type moves from closed to fully open position and the counterbalance mechanism must be constructed to change its counteriorce accordingly. In electric cooking ranges where the broiler element is located in the oven means should also be provided to hold the door slightly ajar in order to vent the oven and keep it from being unduly heated. I

According to our invention we provide a counterbalance mechanism which will yieldingly hold an oven door tightly closed, yieldingly hold it slightly ajar, yieldingly hold it fully open, and will substantially counterbalance it in all positions between closed and fully open positions. Our improved mechanism is designed for use with an oven door having inner and outer walls and a connecting annular flange to provide a chamber within the door. It comprises a lever which is mounted upon a fulcrum carried by a bracket which is suitably secured to the inner wall of the door, a roller which is mounted upon a fixed stud within a range, a fixed abutment within the range and a tension spring which is disposed within the door chamber. The end of the lever adjacent the pivot point is disposed at an angle to the rest of the lever and extends downwardly into the door chamber and has one end of the tension spring connected thereto. The other end of the spring is connected to a tension adjusting screw which is suitably mounted within the door chamber and is accessible through an aperture in the door flange. The upper edge of other end of the lever is generally concave and extends into the range under the roller against which it is yieldingly held in all positions of the door by the tension spring. The under edge of the lever adjacent the free end thereof has a notch formed therein which en gages the fixed abutment when the door is in fully open position. The fixed abutment and the roller cooperate with each other and the lever to limit the opening movement of the door to substantially horizontal position. The tension spring always tends to slightly bias the door toward closed position. The relative positions of the door hinge axis, the roller axis, and the fulcrum for the arm with respect to each other, and the contour of the upper edge of the lever are such as to progressively decrease the biasing force exerted by the spring as the door is moved from fully open to closed position and thus compensate for the constantly changing force exerted by gravity upon the door as it moves from open to closed position. This arrangement substantially counterbalances the door in all positions and prevents slamming of the door in opening and closing. In order to yieldingly hold the door tightly closed, slightly ajar or fully open we provide three spaced shouiders in the upper edge of the lever. When the door is closed one of these shoulders engages the roller rearwardly thereof. When the door is slightly ajar another shoulder engages the roller forwardly thereof, and when the door is fully open the third shoulder engages the roller.

The principal object of the invention is to provide a simplified and improved counterbalance mechanism for a cooking range oven door which will substantially counterbalance the door in all positions between fully open and closed position and prevent slamming of the door in open ing and closing.

Another object of the invention is to provide a mechanism of this character that is so constructed and arranged that it will compensate for the changing force exerted by gravity on an oven door of the drop type as it is moved between open and closed positions.

Another object of the invention is to provide in a mechanism of this character means by which an oven door may be yieldingly held in closed, slightly ajar, or full open positions.

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawings forming a part thereof wherein Fig. l is a fragmentary vertical section through a cooking range showing our improved counterbalance mechanism yieldingly holding the oven door in fully open position, the plane of the section being indicated by the line i! of Fig. 4;

Fig. 2 is a view similar to Fig. 1 showing the oven door being yieldingly held in closed position;

Fig. 3 is a view similar to Fig. 1 showing the oven door being yieldingly held slightly ajar;

Fig. 4 is a fragmentary horizontal section taken on the line 44 of Fig. 1;

Fig. 5 is a fragmentar vertical section taken on the line 5-5 of Fig. 2;

Fig. 6 is a detail section taken on the line 35-43 of Fig. 5;

Fig. '7 is a side elevation of a slightly modified form of lever; and

Fig. 8 is a side elevation of another modified form of lever.

Referring now to the drawings by reference characters, the numeral I indicates a cooking range having an oven compartment 2 which is closed by an oven door 3. The front wall of the range is designated by the numeral 4 and one of the side walls is shown at 5. The numeral 5 designates the bottom of the oven and the numeral 1 designates one of the side walls of the oven which is spaced from the end wall 5 to provide a chamber 8 therebetween.

The oven door 3 comprises an inner rectangular wall 9 having an outwardly extending annular flange Iii, and an outer wall H having an inwardly extending annular flange !2 which telescopes the outwardly extending fiange is and is suitably secured thereto. The walls 9 and H are spaced from each other to provide a chamber l3 therebetween. The door 3 is secured to the front wall 4 of the range i by a pair of hinge members l4, one of which is disposed at each side of the door adjacent the lower end thereof. In opening, the upper end of the door 3 swings outwardly and downwardly from the front wall of the range.

Each hinge member It comprises a bracket i5 and a pivot pin [6. The brackets iii are rigidly secured to the front wall 4 of the range and extend outwardly therefrom and into the chamber 53 of the door 3 through slots li therein. The pivot pins I5 are carried by slides :8 which are secured to the door 3 within the chamber i3. Each of the slides [8 consists of an angle iron having a horizontal leg 20 and a vertical leg ii. The ends of the horizontal legs at are turned downwardly as indicated at 22. The downwardly turned ends 22 slidably engage the outwardly extending flange IQ of the inner wall of the door 3 and the vertical legs 2! bear against the inner face of the door wall 8. Screws which are inserted through elongated slots 2 in the wall 9, hold the slides E8 in adjusted position. One of the pivot pins 16 is welded to each of the horizontal legs 20 of the slide l8,

indicated at 25, and extends outwardly therefrom into an aperture IS in the associated bracket i5. To remove the door 3 from the range the screws 23 are first loosened and then the slides 58 are slid inwardly toward each other by means of the screws 23 thus withdrawing the pivot pins Hi from the apertures IS in the brackets (5. To replace the door 3 it is held in place with the brackets 15 extending in through 4 the slots l1 and then the slides it! are slid outwardly until the ends of the pins it enter the apertures IS in the brackets l5. The screws 23 are then tightened which holds the slides firmly in place.

In order to limit the opening movement of the door 3, to yieldingly hold it in fully open position, slightly ajar, or closed, and to substantially counterbalance the door in all positions between closed and fully open we provide a counterbalance mechanism which comprises a lever 25, a flanged roller 21, fixed abutment 28 and a tension spring 29.

The flanged roller 27 is rotatably mounted upon a fixed shaft 30 carried by a U-shaped bracket 3i which is rigidly secured between the walls 5 and 1 within the chamber 8 in the range 1. The abutment 28 is also carried by the bracket 3|, below and slightly inwardly of the roller 2'3.

The lever 26 is rotatably mounted upon a pin 34 between a pair of ears 35 which extend out through a slot 36, in the inner wall Q of the door, from a cage 31 secured to the door 3 within the door chamber [3. The lever 25 consists of a short section 38 disposed on one side of the pivot pin 34 and a relatively long section 3:) disposed on the other side of the pivot pin at an angle to the section 38. The section of the lever 2-5 extends into the door chamber l3 through the slot 36 and is connected to one end of the tension spring 29. The other end of the spring 29 is connected to a nut 5% on a tension adjusting screw 4| rotatably mounted in a cross bar 42 carried by the cage 3'! adjacent one end thereof. Access is had to the screw s1, for adjusting the tension of the spring 29, through an axially aligned aperture 33 in the annular door flanges H3 and [2. The other section of the lever 25 extends through a slot @5 in the front wall 13 of the range into the chamber 5% and between the roller 2'1 and the abutment 2E. The spring 29 always yieldingly holds the upper edge 58 of the lever 26 in engagement with the roller E'i As the door 3 moves from closed position shown in Fig. 2 to fully open position as shown in Fig. 1 the force exerted by gravity urging the door towards fully open position progressively increases. Conversely as the door is moved from the fully open position shown in Fig. 1 to the closed position shown in Fig. 2 the force exerted by gravity upon the door progressively decreases. Consequently in order to substantially ccunterbalance the door in all positions between closed and fully open positions it is necessary that the counterbalance mechanism be so constructed and arranged that the counterforce exerted thereby against the force exerted by gravity will also progressively change in direct proportion to the change in the force exerted by gravity as the door is moved back and forth between closed and fully open positions. To this end we make the contour of the upper edge 50, or" the lever 26, which bears against roller 21 in the form of a concave compound curve. The curvature thereof is such that the normal to the point of contact thereof with the periphery of the roller 21 progressively varies from substantially vertical to substantially horizontal as the door 3 is moved from closed to fully open position as shown at 5| in Figs. 1 and 2. The roller 21 and the lever 26 cooperate to progressively vary the effective force exerted by the spring 29 during opening and closing of the door. When the door is closed with the normal 5| substantially vertical as shown in Fig. 2 the efiective force of the spring 29 is at its minimum; and when the door is fully open with the normal 5| substantially horizontal the eifective force of the spring 29 is at its maximum.

In order to limit the opening movement of the door 3 to substantially horizontal position we provide a notch 52, in the lower edge of the lever 26, which engages the fixed abutment 23 when the door is in open position. As the door approaches fully open position the roller 21 forces the lever 26 downwardly until the notch 52 engages the abutment 29 after which the roller 21 and the abutment 28 cooperate with each other and with the lever 26 to prevent further opening movement of the door.

In order to yieldingly hold the door 3 tightly closed, slightl ajar or fully open we provide three spaced shoulders 53, 54 and E5 in upper edge 53 of the lever 25. When the door is closed the shoulder 53 engages the roller 27 as shown in Fig. 2; when slightly ajal the shoulder 54 engages the roller 2! as shown in Fig. 3, and when fully open the shoulder 55 engages the roller 27 as shown in Fig. 1. During the initial opening movement of the door sufficient extra force must be manually applied to the door to depress the lever 26 until the shoulder 53 passes the roller 2'1. During the final closing movement of the door 3 from the slightly ajar position shown in Fig. 3 sufficient extra force must be manually applied to the door to depress the lever 25 until the shoulder 5 passes the roller 21; and during the initial closing movement of the door suflicient extra force must be manually applied to the door to move the shoulder 55 away from the roller 2?.

In Fig. 7 we have shown a slightly modified form of lever 23 in which the contour of the upper edge 59 is slightly different from that shown in 1 to 3. Otherwise the construction and operation of this lever are substantially the same as the lever shown in Figs. 1 to 3 and like reference characters are applied to similar parts.

In Fig. 8 we have shown a further modified form of lever 26. In this form the contour of the upper edge 53 is slightly different from that shown in either Fig. l or Fig. 7, and the shoulders 53, 54 and 55 have been eliminated. In place of the shoulder 53 we provide a notch 56 which engages the roller 27 to yieldingly hold the door tightly closed. No means are provided to yieldingly hold the door slightly ajar or fully open. Otherwise the construction and operation of this form of lever are the same as the levers shown in Figs. 1 and 7, and like reference characters are applied to similar parts.

From the foregoing it will be apparent to those skilled in this art that we have provided a very simple and eflicient mechanism for accomplishing the object of the invention.

It is to be understood that we are not limited to the specific constructions shown and described herein as various modifications may be made therein within the scope of the appended claim.

What is claimed is:

A cooking range comprising a cabinet having a front wall, an oven within said cabinet, an opening into said oven through said front wall, an oven door by which said opening is closed, hinge means by which said door is secured to said front wall for movement between a vertical closed position and a substantially horizontal open position, and counterbalance mechanism by which said door is yieldingly held in fully open and closed positions, and is substantially counterbalanced in all positions between said fully open and said fully closed positions; said oven door comprising spaced inner and outer walls and a connecting peripheral wall defining a, door chamber therebetween; and said counterbalance mechanism comprising a fixed shaft within said cabinet, a roller mounted on said fixed shaft, a fixed abutment in said cabinet below said roller, a lever pivotally secured to the said inner wall of said door with one end of said lever being disposed within said door chamber in all positions of said door and the other end of said lever being disposed within said cabinet between said roller and said fixed abutment, said lever having a generally concave upper edge and a notch formed in the lower edge thereof adjacent the said other end thereof, said roller, said lever and said fixed abutment being so disposed with respect to each other that said roller cams said lever downwardly until said notch engages said fixed abutment as said door approaches fully open position, said lever cooperating with said roller and said fixed abutment to limit the opening movement of said door, and a tension spring disposed wholly within said door chamber and having one end thereof connected to the said one end of said lever within said door chamber and the other end thereof connected to said door within said door chamber, said spring yieldingly holding the concave upper edge of said lever in engagement with the under portion of said roller.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,922,587 Hoifstetter Aug. 15, 1933 2,313,582 Rees Mar. 9, 1943 2,401,977 Smallwood June 11, 1946 2,425,365 Davidson Aug. 12, 1947 2,447,341 Johnston Aug. 17, 1948 2,513,414 Jones July 4, 1950 2,539,151 Mills Jan. 23, 1951 2,541,942 Sherman Feb. 13, 1951 FOREIGN PATENTS Number Country Date 173,306 Great Britain Dec. 28, 1921 

